Abstract:

The Point macquarie-Tacking Point coastline provides excellent exposures of the accretionary subduction complex and youger magmatic arc rocks that make up much of the New England Fold Belt (also known as the New Enagland Orogen) in north-eastern New South Wales. None geological units, including six formally defined here (Port macquarie Serpentineite, Rocky Beach Metamorphic Melange, Tacking Point Gabbro,Town beach Diorite, Nobbys Beach Lamprophyre and Sea Acres Dolerite) have been identified along this coastline tract. The kaikeree Metadolerite has been redefined. The oldest rocks are prograde lawsoniate eclogite and retrograde blueschist blocks embedded in the chlorite-actinolite schist matrix of the Rocky Beach Metamorphic Melange that occurs as a slab within te Port Macquarie Serpentine. The Port Macquartie Serpentine is a product of alteration of cumulate ultramafic rocks of a c.530 Ma forearc ophiolote. The Watonga Formation is a mostly broen formation that consists of Middle-Late Ordovician pelagic rocks, the mafic oceanic substrate on which these were deposited; younger basalt and olistostromes of porbable ocean island origin; and stuff, sultstone and sandstone infered to be trench fill accreted in te Late Ordovician-Carbvoniferous interval.